Agriculture Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, OK 73401, USA.
J Anim Sci. 2013 Jan;91(1):508-15. doi: 10.2527/jas.2012-5527. Epub 2012 Oct 9.
Stocker cattle production practices may affect subsequent performance of cattle in economically meaningful ways. Literature was reviewed to summarize possible carryover effects of stocker cattle management on finishing performance and carcass traits. The most consistent effects of stocker phase practices on finishing-phase and carcass performance of cattle appear to be explained by changes in placement weight of feeder cattle. Increasing placement weight typically is confounded with age at placement, ADG during stocker period, and duration of the stocker period. It may also be confounded with other factors, such as season of grazing and/or finishing. Data from studies comparing calf-fed to yearling-fed cattle indicate that as age or BW at feedlot entry increased, finishing ADG, DMI, and HCW increased (P<0.01) whereas G:F and days on feed decreased (P<0.01). As age and BW at feedlot entry increased, marbling score decreased (P<0.01) whereas Warner-Bratzler shear force increased (P<0.01). Studies with yearling cattle entering the feedyard after a forage-based backgrounding phase indicate that as backgrounding ADG increased, finishing ADG, DMI, and days on feed decreased (P<0.01) yet HCW and ribeye area increased (P<0.01) with no effect (P=0.45) on marbling. Stocker cattle systems are complex, integrated systems in which producers typically seek to maximize their own economic return with little regard for subsequent performance. If cattle are owned across both stocker and finishing phases of production, then management decisions should focus on maximizing return over the entire ownership period and not just within one segment of ownership. Of the traits of feeder cattle that can be affected by stocker cattle systems, BW is the primary determinate of their value when they are placed into commercial feedyards.
育肥牛生产实践可能会以有经济意义的方式影响牛随后的表现。本文综述了育肥牛管理对肥育性能和胴体性状的可能延续效应。育肥期管理措施对牛肥育期和胴体性能的影响最为一致,其原因似乎是育肥牛的初始体重发生了变化。通常,增加初始体重与育肥期的年龄、育肥期的日增重和育肥期的持续时间有关。它也可能与其他因素(如放牧和/或育肥季节)混淆。比较犊牛育肥和青年牛育肥的研究数据表明,随着牛进入育肥场时的年龄或体重增加,育肥的日增重、采食量和活重增加(P<0.01),而饲料转化率和育肥天数减少(P<0.01)。随着牛进入育肥场时的年龄和体重增加,大理石花纹评分降低(P<0.01),而 Warner-Bratzler 剪切力增加(P<0.01)。对经过基于牧草的育肥前期后进入育肥场的青年牛的研究表明,随着育肥前期的日增重增加,育肥的日增重、采食量和育肥天数减少(P<0.01),但活重和肋眼面积增加(P<0.01),大理石花纹无影响(P=0.45)。育肥牛系统是一个复杂的、综合的系统,生产者通常只关注自身的经济回报,而很少考虑随后的性能。如果牛在育肥和育肥两个阶段都归生产者所有,那么管理决策应该着眼于在整个所有权期间实现回报最大化,而不仅仅是在所有权的一个阶段实现回报最大化。在可以通过育肥牛系统影响的育肥牛特性中,体重是它们进入商业育肥场时价值的主要决定因素。